Rf readers are commonly used in industrial plants to identify and track items being manufactured. Typically, an rf tag is placed on an item to be monitored. The rf tag contains relevant data pertaining to and identifying the item. As the rf tag passes near the rf reader, a directional antenna emits rf signals in the range of 134 KHz towards the rf tag. The emitted rf signals induce an AC current in the rf tag. The AC current is used to "power-up" the rf tag thereby enabling the rf tag to transmit response signals from the rf tag back to the rf reader. The response signals typically contain the aforementioned relevant data pertaining to and identifying the tagged item.
Commonly, rf readers are placed on standard mountings built into the manufacturing facility. These standard mountings are located throughout the manufacturing facility wherever monitoring devices may be needed. Often, the mountings require that the rf reader be placed into tightly cramped locations. Thus, conventional rf readers are separated into two distinct portions, a uni-directional antenna portion and the read/write electronics portion. The two distinct portions of the rf reader are connected to each other by, for example, a cable or other extended electrical connector. Such cable or other extended electrical connectors crowd the manufacturing environment, serve as a source of power loss, and are a source of electrical noise. In addition to the noise generated by cable or other extended electrical connectors, noise is also generated by the reader power supply. The generated noise can make it difficult to clearly receive response signals transmitted by the tagged item.
In addition to the problems associated with cables or other extended electrical connectors, in many instances, due to the placement of the standard mountings, numerous uni-directional antennas must be located near the path of the of the item to be monitored. That is, because the antenna portion is attached to standard mountings, the uni-directional antenna may not always be focused directly towards the path of the tagged item. Thus, in order to insure that the rf tag on the item is incident with the rf signals emitted from the antenna, several antennae are located on numerous respective standard mountings near the path of the tagged item. As a result, the cost of such an rf monitoring system is increased, and the amount of valuable manufacturing space required for such a system is also increased.
Furthermore, many conventional rf reader units contain numerous switches and buttons for programming and setting operating parameters of the rf reader unit. The buttons and switches further limit the rf reader mounting position possibilities. Additionally, the buttons and switches further increase the size of the rf reader unit and limit the extent to which the size of the read/write electronics can be reduced.
Consequently, the need has arisen for an rf reader unit which can be placed in a cramped location, which can be disposed on standard mountings, which does not suffer from power loss or electrical noise due to a cable or other type of extended electrical connection between the antenna portion and the read/write electronics portion, which does not generate noise which interferes with response signals from the tagged item, which is able to be focused towards the path of a tagged item without requiring numerous additional rf reader units, and which does not require numerous buttons and switches to program and set operating parameters for the rf reader unit.